2013 Pathfinder with P0420 (my daughter's vehicle). Long history of this code coming and going. Had a shop look at it. They replaced the cat as well as spark plugs and a list of other things. Fixed it for less than a year. Code would come and go until lately it just stayed on. No other codes. So, I committed myself to check everything. First up was to look for leaks in the intake system. I did not get very far. I found the intake boot had a long slit in the rubber on the bottom near the throttle body. It probably did not leak a lot of air as there were no other codes and the fuel trims were indicating maybe a bit lean. Rather than look farther, I cleaned the throttle body a bit, installed a new air filter and a new boot. The IM's were not ready as a code clear had been done earlier (week or so ago) and the P0420 was a permanent code (as well as stored and pending). I did not do a drive cycle either. I just let my daughter drive the car as she would normally drive it. Within 3 days, the stored and pending codes cleared. Another 3 days, the permanent code cleared and the check engine light went off. She continues to drive it and we will see if this was THE problem or just A problem.
I’m also in the same situation, I had the code, replaced the catalytic converter and the flex down pipe . Now the code is still ON. I will try to get a new air filter . Good idea
@@Icubela Air filter alone will not fix it. In my case the slit in the boot was after the MAF and before the throttle body allowing extra unaccounted air in the system. Only time will tell if this was the source if the cat code.
It appears to be A problem, not THE problem. I checked for exhaust leaks and found none. The cat was replaced a year ago and from what I can tell, the engine is running clean. I've been down the cataclean route before, will try again...anything but pull that cat.
so did i, car had never had any codes. got some gas (assuming it was bad gas) and its been on since. being the car is old, but well maintained im just gonna replace o2 sensors for peace of mind
@@alihamzia1896after replacing both o2 sensors. Still got the code… ordered an exhaust manifold after my dad did some ol skool troubleshooting. So it was taking in air but when he checked both exhaust pipes their air temps were cool and barely putting out. And a few other things he checked it was confirmed the exhaust manifold was clogged. Codes went off, better gas mileage and purring like a kitten.
Great video! I love that you talk in an organized fashion and get right to the point! 2009 Murano SL with the P0420 code on/off for several years. Cataclean and lacquer thinner in the gas tank sometimes turns of the light but less and less lately. RPMs are smooth, and power is the same as always. Can't see any holes in the exhaust. Does this sound like it needs a new CAT (please tell me no because I live in CA!)? Or more likely the O2 sensors?
First, great video and explanation. Could be several causes and you hit on each. Second, now you can’t pass an inspection here in Texas with a check engine light on, especially with this emissions code! My 2012 Nissan Titan runs great! I drove it to North Dakota last summer with this code showing from Houston! But it won’t pass inspection and I can’t get registration tags because of this code! Bunch of crap!
@@garyboswell6739 I meant 1 gallon gallon of laquer thinner I did worked out for me. After run for a while check engine light off and passed emissions test
I got this code found my ground strap broken at the exhaust pipe near the sensor I replace the strap & removed sensor &. Clean now no more codes been 2 years.
@@jeffreymarley6877 they wanted to replace both sensors for about $630. I declined. Car is running fine using CATACLEAN and resetting and clearing the code. Usually lasts a month or 2 and I reset the code by unhooking the negative battery wire. Car is running fine.
Auto shop wants to replace both o2 sensors. ,$630..... hell no. I ll keep using Cataclean. $1,400 for new converter. Hell no. That's more than my 08 Altima is worth.
@@rickyblaze-starwarsbattlef4413 nope. Works great. No check engine light in months. I'll keep using it quarterly or whenever the light comes back on.
very good vid., & I do have question☝️ I gotta P0420 & p2097(swapd that oxy sensor, still-there), however the scanner trim monitor, says both these codes are from running lean(+>0-10 trim) not rich(which I beleive they USUALLY are).. any guesses on that cunundrum?(cats pretty new too & the lean readings are in BOTH banks btw)✋
I just replaced both front and rear cat, o2 sensors, plugs, coul packs AND mass air sensor and still getting p0420 on my w015 Altima 2.5 s9me 0kease help
Can I gut the exhaust manifold cat AND the cat under the car? If so, which sensor would I have to space out? Or do I have to space out both sensors since I gutted out the manifold cat and under the car cat. 2012 Altima 2.5. Thanks in advance!
Hello my 2010 Nissan altima runs beautiful but when I scan it it says P0420 it has alot of power so I think ur right about taking it on highway I put cleaner for system so can u let me know why it still shows P0420 thx
I had the p0420 code and it seems the exhaust is smelling rich. Code was reset and no codes for a few weeks now. Any ideas. Car runs good with acceleration. 2008 Altima
I got 2 codes on my 2015 Sentra. P0171 and P0420. I’m pretty sure p0171 is triggering p0420. Cat replaced and exhaust leak fix already. Anyone had this same issues before?
It needs to be diagnosed, but if the 02 sensors are good, the CAT might be going bad. You can try to run some CATA Clean or similar through and see if it clears.
Each engine has its own firing order, which needs to be looked up. Google your engine firing order and look at Google Images, they usually have it. The side with cylinder 1 is Bank 1.
@@managed9348 yep. It never came back. The code could be triggered when going up steep inclines or during cold weather. That's when I've noticed it. Car passed smog too no problem
![How to Fix NISSAN P0420 Engine Code in 3 Minutes [3 Methods / Only $19.99]](http://i.ytimg.com/vi/NESVCrsaXe4/mqdefault.jpg)
2013 Pathfinder with P0420 (my daughter's vehicle). Long history of this code coming and going. Had a shop look at it. They replaced the cat as well as spark plugs and a list of other things. Fixed it for less than a year. Code would come and go until lately it just stayed on. No other codes. So, I committed myself to check everything. First up was to look for leaks in the intake system. I did not get very far. I found the intake boot had a long slit in the rubber on the bottom near the throttle body. It probably did not leak a lot of air as there were no other codes and the fuel trims were indicating maybe a bit lean. Rather than look farther, I cleaned the throttle body a bit, installed a new air filter and a new boot. The IM's were not ready as a code clear had been done earlier (week or so ago) and the P0420 was a permanent code (as well as stored and pending). I did not do a drive cycle either. I just let my daughter drive the car as she would normally drive it. Within 3 days, the stored and pending codes cleared. Another 3 days, the permanent code cleared and the check engine light went off. She continues to drive it and we will see if this was THE problem or just A problem.
I’m also in the same situation, I had the code, replaced the catalytic converter and the flex down pipe . Now the code is still ON. I will try to get a new air filter . Good idea
@@Icubela Air filter alone will not fix it. In my case the slit in the boot was after the MAF and before the throttle body allowing extra unaccounted air in the system. Only time will tell if this was the source if the cat code.
It appears to be A problem, not THE problem. I checked for exhaust leaks and found none. The cat was replaced a year ago and from what I can tell, the engine is running clean. I've been down the cataclean route before, will try again...anything but pull that cat.
good solid informative video. he hit on all the culprits without all the baloney
I got this code once AFTER getting gas. I put cat cleaner in it and made sure the cap was tight. Fixed the problem. Your mileage may vary though.
same , its happened twice,
so did i, car had never had any codes. got some gas (assuming it was bad gas) and its been on since. being the car is old, but well maintained im just gonna replace o2 sensors for peace of mind
mine got fixed after this @@will6295
@@will6295same situation, did you fix it by chance?
@@alihamzia1896after replacing both o2 sensors. Still got the code… ordered an exhaust manifold after my dad did some ol skool troubleshooting. So it was taking in air but when he checked both exhaust pipes their air temps were cool and barely putting out. And a few other things he checked it was confirmed the exhaust manifold was clogged. Codes went off, better gas mileage and purring like a kitten.
Excellent video. Clear and concise. I'm gonna check for exhaust leaks and if none, try Cataclean.
Great video! I love that you talk in an organized fashion and get right to the point! 2009 Murano SL with the P0420 code on/off for several years. Cataclean and lacquer thinner in the gas tank sometimes turns of the light but less and less lately. RPMs are smooth, and power is the same as always. Can't see any holes in the exhaust. Does this sound like it needs a new CAT (please tell me no because I live in CA!)? Or more likely the O2 sensors?
replace the PCV valve and the crankcase hoses they could be cracked ..i have a 05 frontier 173k and the light finally went out
Replace PCV valve and check the 3 PCV hoses especially the crankcase hoses,,, Thats what FINALLY deleted my code 0420
Hey..is that up near head..i just changed valve cover and they mentioned pcv valve
@@daltropical5236 on my 05 frontier V6 It is located on the right side rear of the valve cover follow hose from intake to pcv valve
@@jmar2229 👍will check it out tmrw thank for reply
First, great video and explanation. Could be several causes and you hit on each. Second, now you can’t pass an inspection here in Texas with a check engine light on, especially with this emissions code! My 2012 Nissan Titan runs great! I drove it to North Dakota last summer with this code showing from Houston! But it won’t pass inspection and I can’t get registration tags because of this code! Bunch of crap!
Half tank of gas 2 gallons of laqued thinner
Carlos. So 2 gallons of laquer thinner did not hirt anything?@@CarlosChataing
@@garyboswell6739 I meant 1 gallon gallon of laquer thinner I did worked out for me. After run for a while check engine light off and passed emissions test
I got this code found my ground strap broken at the exhaust pipe near the sensor I replace the strap & removed sensor &. Clean now no more codes been 2 years.
Very informative, thank you.
Dude legit solid video!
0420 code again on my '08 Altima , they believe it's the o2 sensor not sure if it's upstream or downstream
What did you find?
@@jeffreymarley6877 they wanted to replace both sensors for about $630. I declined. Car is running fine using CATACLEAN and resetting and clearing the code. Usually lasts a month or 2 and I reset the code by unhooking the negative battery wire. Car is running fine.
@@Tngoz Thank you!
Thank you so much.. you've got a new subscriber
Great video. Thank you
Auto shop wants to replace both o2 sensors. ,$630..... hell no. I ll keep using Cataclean. $1,400 for new converter. Hell no. That's more than my 08 Altima is worth.
Cataclean made it worse for me. Has this happened to you?
@@rickyblaze-starwarsbattlef4413 nope. Works great. No check engine light in months. I'll keep using it quarterly or whenever the light comes back on.
Cheap replacement catalytic converters don't have the quality and or the quantity of precious metals in there and fail.
90s vibe he should keep this flow
very good vid., & I do have question☝️
I gotta P0420 & p2097(swapd that oxy sensor, still-there), however the scanner trim monitor, says both these codes are from running lean(+>0-10 trim) not rich(which I beleive they USUALLY are).. any guesses on that cunundrum?(cats pretty new too & the lean readings are in BOTH banks btw)✋
I had the catalyic converter code and the code 3 spark plug. My car is knocking like something is loose. My car was very hot when I parked the car.
What was the fix? I have the same thing going on.
I just replaced both front and rear cat, o2 sensors, plugs, coul packs AND mass air sensor and still getting p0420 on my w015 Altima 2.5 s9me 0kease help
Can I gut the exhaust manifold cat AND the cat under the car? If so, which sensor would I have to space out? Or do I have to space out both sensors since I gutted out the manifold cat and under the car cat. 2012 Altima 2.5.
Thanks in advance!
Hello my 2010 Nissan altima runs beautiful but when I scan it it says P0420 it has alot of power so I think ur right about taking it on highway I put cleaner for system so can u let me know why it still shows P0420 thx
Engine light on ,with that code. I think my senor is bad,I have put cat cleaning in,I have not lost any power on my 2011 Xterra Pro 4x.
I have a new cat and new upstream and downstream sensors on a 2012 Sentra. What else could it be? Also new plugs, coils, spark plug wires.
Leak on exhaust manifold, wrong ratio 🤷♂️
Did you ever find out?
@@LottoI95no and I sold the car, they’re taking it to Mexico where there are no smog regs
I have 420 code but the problem was no good ground? Use new ground, problem solved
Thanks !
what YEAR NISSAN? It matters
Ok before I got this code I got a code of a bad o2 sensor.
I had the p0420 code and it seems the exhaust is smelling rich. Code was reset and no codes for a few weeks now. Any ideas. Car runs good with acceleration. 2008 Altima
I had a miss firing issue on cylinder 3, I fix that then I got the P0420 code, could the cleaner , clean out the un- burned fuel ?
It is possible. You could take it out for a drive and heat up the catalytic converter to burn any excess fuel out.
Thanks, I put a cleaner in, drive to work , clear the code, I'll see what happens.
I also had a misfire in cylinder 2. I fixed the problem. Now I’m getting the same p0420 code. Did the cleaner fix your problem? Thanks in advance.
I got 2 codes on my 2015 Sentra. P0171 and P0420. I’m pretty sure p0171 is triggering p0420. Cat replaced and exhaust leak fix already. Anyone had this same issues before?
this is what my nissan 09 altima is throwing did you ever find anything out ?
If it's just a sensor issue, can I just drive her or will it cause more issues
Upstream sensors no, fix it. Those control fuel trims. Downstream sensor let it ride.
@@fritzthecat9451 so bad mpg?
@@Joe-eg7ml bad mpg at best. Smoked piston rings and a really clogged cat at worst.
I have just the code but nothing is running bad or off so what should I do
It needs to be diagnosed, but if the 02 sensors are good, the CAT might be going bad. You can try to run some CATA Clean or similar through and see if it clears.
Where is located the bank 1? Is it the right or left side? I’m looking to buy a catalytic converter but I don’t know what side is bank 1.
Each engine has its own firing order, which needs to be looked up. Google your engine firing order and look at Google Images, they usually have it. The side with cylinder 1 is Bank 1.
I just fix it by removing the code 😅
Does it really work?
@@managed9348 yep. It never came back. The code could be triggered when going up steep inclines or during cold weather. That's when I've noticed it. Car passed smog too no problem
How did you remove the code?
@@oladissa with a computer
@@managed9348 thanks
Ohhh
I’m getting P0420 and P0303 am I doomed?
Me too what was the issue
You'll only be doomed if you keep electing the dems to power. ;-)
I got this code on my Altima 2019..i wonder how a car like this model got this code..🫠
Btw i just rest the code and wait for the next appearance
Thanks! Very informative